/*******************************************************************************
 * Copyright (c) 2013, Daniel Murphy
 * All rights reserved.
 * 
 * Redistribution and use in source and binary forms, with or without modification,
 * are permitted provided that the following conditions are met:
 * 	* Redistributions of source code must retain the above copyright notice,
 * 	  this list of conditions and the following disclaimer.
 * 	* Redistributions in binary form must reproduce the above copyright notice,
 * 	  this list of conditions and the following disclaimer in the documentation
 * 	  and/or other materials provided with the distribution.
 * 
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
 * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
 * IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT,
 * INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
 * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
 * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
 * POSSIBILITY OF SUCH DAMAGE.
 ******************************************************************************/

package org.jbox2d.pooling.normal;

import org.jbox2d.pooling.IOrderedStack;

public abstract class CircleStack<E> implements IOrderedStack<E> {

	private final Object[] pool;
	private int index;
	private final int size;
	private final Object[] container;

	public CircleStack (int argStackSize, int argContainerSize) {
		size = argStackSize;
		pool = new Object[argStackSize];
		for (int i = 0; i < argStackSize; i++) {
			pool[i] = newInstance();
		}
		index = 0;
		container = new Object[argContainerSize];
	}

	@SuppressWarnings("unchecked")
	public final E pop () {
		index++;
		if (index >= size) {
			index = 0;
		}
		return (E)pool[index];
	}

	@SuppressWarnings("unchecked")
	public final E[] pop (int argNum) {
		assert (argNum <= container.length) : "Container array is too small";
		if (index + argNum < size) {
			System.arraycopy(pool, index, container, 0, argNum);
			index += argNum;
		} else {
			int overlap = (index + argNum) - size;
			System.arraycopy(pool, index, container, 0, argNum - overlap);
			System.arraycopy(pool, 0, container, argNum - overlap, overlap);
			index = overlap;
		}
		return (E[])container;
	}

	@Override
	public void push (int argNum) {
	}

	/** Creates a new instance of the object contained by this stack. */
	protected abstract E newInstance ();
}
